Hi all. I just joined WW and the activity points weren't really touched on when I met with the leader. Let's say that I earn 3 activity points today, do I have to eat them today, or are they like flex points and can be used throughout the week?

You can use them throughout the week.
In the "old days" you used them or lost them, but not anymore. That being said, if you exercise heavily it is a good idea to eat a least a couple of extra of your AP points (especially protein).

Good luck with your journey!

Thanks. I actually don't exercise much right now, but if it means I might have some extra points to spend, it makes it much more appealing!